Hip joint endoprostheses may help to significantly improve the quality of life of patients whose natural hip joint has been damaged by attrition or disease. In the course of time, however, a loosening of the hip joint endoprosthesis may occur, which may necessitate a replacement of the hip joint endoprosthesis by a new hip joint endoprosthesis. In the context of hip joint endoprosthesis loosening, extensive periprosthetic osteolysis is frequently observed. This may make a sufficiently stable anchoring of the new hip joint endoprosthesis difficult, in particular in cases of metaphyseal bone defect.
A revision endoprosthesis according to the state of the art is disclosed, for example, in DE 43 20 086 A1 and in DE 43 20 086 C3. The revision endoprosthesis comprises a stem which may be inserted into the patient's femur, an extension section which may be attached to the stem and a joint ball section which may be attached to the extension section or, alternatively, to the stem. The joint ball section comprises a joint ball attached thereto which can be inserted into an artificial joint socket fixed to the patient's pelvic bone.
The stem of a revision endoprosthesis may be adapted for uncemented diaphyseal anchorage and bridging of the damaged metaphyseal bone bed. Thus, a significant amount of mechanical load may be exhibited to the diaphysis of the femur, leading to a reduced mechanical load in the damaged metaphysis. In situations without metaphyseal defect augmentation and for large diameter stems, this may entail an insufficient mechanical load of the metaphysis and a subsequent atrophy.
To reduce this problem, it has been proposed to fill metaphyseal defects with autogenous and/or allogenic bone material and to impact the bone material. Thus, bone regeneration with corresponding bone remodeling processes and firm integration of the revision endoprosthesis may be obtained.
To introduce bone material into the metaphyseal defects and to impact the bone material, in methods of implanting a revision endoprosthesis according to the state of the art tools such as, for example, surgical chisels or other blunt objects are used.
A problem of the methods according to the state of the art for introducing and impacting bone material into metaphyseal defects is that it may be difficult to introduce a surgical chisel or other blunt object into the metaphyseal defect.
Another problem of the methods according to the state of the art for introducing and impacting bone material in metaphyseal defects is that metaphyseal defects may be insufficiently filled with bone material, which may lead to a formation of cavities between the revision endoprosthesis and the femur. The presence of the cavities may lead to an insufficient anchorage of the revision endoprosthesis in the femur.
Hence, there is a need for an apparatus for impacting bone material, an impaction tool for impacting bone material, a method of impacting bone material and a modular system for providing a hip joint endoprosthesis which may help to overcome some or all of these problems.